Sun louver installed outside is more scientific than inside, and the shading effect is better too. Traditional shutter is installed inside of window which formed a false shading impression from the visual illusion. In fact, heat has entered indoor and created green house effect. While outdoor louver is not affected by such green house effect, it blocks sunlight meanwhile absorbs and reflects heat too to save energy. In addition, architectural louvers not only can protect buildings but also increases stereo feeling and artistic effects.